1. Field of the Invention
The present invention relates to an image capture device and an image processing method. In particular, the invention relates to a technology of performing restoration processing of restoring a moving image captured through an optical system on the basis of a point spread function (PSF) or an optical transfer function (OTF) of the optical system.
2. Description of the Related Art
Restoration processing for a captured image is processing of obtaining characteristics of degradation (PSF or OTF) caused by aberration and the like of an optical system (photography lens) in advance and restoring a captured image (degraded image) to a high-resolution image through restoration processing performed by using a restoration filter which is generated on the basis of a PSF or OTF.
Between a PSF and OTF, there is a relationship of Fourier transform, where the PSF is a real function and the OTF is a complex function. As things having information equivalent thereto, there are a modulation transfer function or an amplitude transfer function (MTF) and a phase transfer function (PTF), and these functions respectively indicate an amplitude component and a phase component of an OTF. An MTF and a PTF have amounts of information equivalent to those of an OTF and a PSF.
In the past, when a high-resolution image has been restored from a degraded image, in case where the restoration processing has been performed using a restoration filter which is generated such that it becomes one ideal point after the restoration, a problem has arisen in that a high-frequency component is excessively restored (overcorrected) and image disturbance occurs. In order to solve this problem, the image restoration method described in JP2006-238032A performs the restoration processing through a restoration filter having a fine point spread even after the restoration so as to suppress roughness or disturbance of the image caused by the high-frequency component of the restored image by attenuating the high-frequency component.
The image capture device described in JP2008-11492A is characterized in that a first filter used in restoration processing for a still image is different from a second filter used in restoration processing for a moving image. In particular, by making a filter size of the second filter smaller than a filter size of the first filter, it is possible to achieve reduction in a time period (real time) of the restoration processing for the moving image and accurately perform the restoration processing on the still image.